Effect of feeding different sources of selenium on growth performance and antioxidant status of broilers

ABSTRACT

1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0–35 d broiler chicken diets.

2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source.

3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0–35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001).

4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.     

Warm weather transport of broiler chickens in Manitoba. I. Farm management factors associated with death loss in transit to slaughter

This observational study was conducted to identify flock of origin level factors associated with mortality during transport to slaughter of 1 090 733 Manitoba broiler chickens in spring and early summer. The death loss in transit was 0.346% (3778 birds). Death loss on the farm of origin during the growing phase of production and bird body weight at slaughter were associated with increased mortality in-transit. Death loss during production significantly exceeded, while crowding of growing birds was significantly less than, European proposed animal welfare standards.     

Warm weather transport of broiler chickens in Manitoba. II. Truck management factors associated with death loss in transit to slaughter

This observational study was conducted to identify the cause of death and load level factors associated with mortality in 1 090 733 Manitoba broiler chickens transported to slaughter in spring and early summer. Death loss in transit was 0.346% and accounted for 19% of the total carcass condemnation. The death loss pattern was clearly bimodal, with a low death loss in 180 of 198 shipments. Cumulative death loss during the growing phase of production was consistently associated with increased transport mortalities in load level models and when comparing high death loss with low death loss truckloads. High ambient temperature at the time of slaughter and loading density of the truck were the major factors associated with exceptional death loss.     

Food provisioning strategies,food insecurity,and stress in an economically vulnerable community: the Northern Cheyenne case

Living in poverty is associated with high levels of protracted stress associated with health problems. Economic and food insecurity are particularly poignant aspects of poverty and condition the work of securing basic daily needs of families. Recent studies suggest that levels of stress increase as family food needs rise. This paper presents new findings which clarify the relationship of food provisioning to stress levels, by examining actual food provisioning strategies and food insecurity among the Northern Cheyenne Indians of southeastern Montana. Results clearly show that stress varies by types of food acquisition strategies. Contrary to our expectations, more complex strategies, including relatively unpredictable and cumbersome food provisioning activities, are not linked to higher stress levels in our analysis. Controlling for food security levels, households using a combination of local programs and informal subsistence sources are the least stressed, despite the demands of managing a large number of food sources. Households primarily using Food Stamps are the most likely to experience high levels of stress. Interviews with Food Stamp recipients show that potential sources of stress include inadequate allocations of Food Stamps, difficulty achieving and maintaining eligibility, challenges to complying with paperwork and appointment requirements, as well as personal obstacles and community barriers to making food stamps last. Analyses indicate that contradictions between local cultural norms for food provisioning and the realities of food insecurity in this context promote strategies emphasizing greater independence from federal food programs.     

Time to critical overcrowding of Manitoba swine barns in the event of restriction on animal movement

Canada maintains a stamping-out policy for control of foreign animal disease. Integral to stamping out, there are obligatory animal movement restrictions that, over time, can result in severe animal welfare problems. The purpose of this study was to estimate the time to critical overcrowding in a sample of Manitoba swine farms, if they were placed under movement restriction. Time to critical overcrowding in both static and dynamic populations was estimated by modeling swine growth and projecting anticipated on-farm stocking density through time and comparing it with a standard maximal stocking density. The time to critical overcrowding of 15 isowean piglet production units was 0.66 +/- 0.88 weeks. On average, 7 isolated nursery facilities reached critical overcrowding in 52 +/- 14 days and 5 farrow-to-finish operations reached critical overcrowding in 43 +/- 18 days. Animal welfare concerns should be included in contingency plans to control foreign animal disease.     

Minimum space allowance for transportation of swine by road

Space allowance for animals in transit is a consistent concern in many countries that are developing codes of practice and regulations to assure humane treatment of food producing animals. The minimum space allowance requirements for a broad size range of swine in transit has not been well described or scientifically substantiated. A maximal loading pressure recommendation for pigs weighing from 5 to 250 kg was derived by a consultative process involving the swine transportation industry, animal welfare groups, and a literature review. The recommended maximal loading pressure under ideal conditions for swine loaded in groups can be described as a hoerl model y = (37.53)(0.9969)w(W0.5008), where y = loading pressure in kg body weight/m2 and W = average animal body weight in kilograms.     

Postweaning mortality in Manitoba swine

A case-control study to investigate the contribution of postweaning multisystemic wasting syndrome (PMWS) and Porcine circovirus type 2 (PCV-2) to deaths among piglets of nursery age (19 to 68 d) in Manitoba indicated a significant positive association between PCV-2 infection and an increased mortality rate in nursery pigs. The clinical syndrome PMWS was seldom recognized in case or control herds; however, PCV-2 infection was widespread at the herd level. Other factors more strongly associated with increased piglet mortality rate than herd level PCV-2 infection were Mycoplasma hyopneumonia infection, porcine reproductive and respiratory syndrome (PRRS), and diarrhea caused by Eschericia coli K88. Management factors associated with case herd status included close proximity to other herds, larger number of sows supplying pigs to the nursery, larger range in age and weight going into the nursery, the moving of lightweight pigs into another nursery room at the end of the nursery fill, and not using spray-dried plasma in the 1st nursery ration. These results highlight the host-agent-environment triad leading to high nursery-barn mortality rates.     

Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei

A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates.